I would like to use mbeddr's grammar cells in MPS as shown here and in the linked video.
Therefore, I followed the instructions, downloaded the latest stable platform-distribution_2017_2_0.zip and copied all the plugins into my MPS 2018.1. Although the version numbers don't fit perfectly, after some restarting all plugins are without any errors (in the plugin manager).
Now, I don't know how I can use them in my own projects. Do I have do add somewhere something? Anything I have to pay attention to?
You have to import the grammarcells language into the editor where you want to use it. Go to the editor where you want to use grammarcells, press Ctrl/Cmd+L+L, type "grammarcells" to find it, and then press Enter to import them. After that, you will be able to insert grammar cells into your editor.